1. Field of the Invention
The present invention relates to a dewatering apparatus of filter belt type, i.e., an apparatus in which sludge to be fed into a space between double filter belts is dewatered by pressing by means of rollers.
2. Description of Related Art
As this kind of art, there has hitherto been known an apparatus as disclosed, e.g., in Japanese Published Examined Patent Application No. 20360/1990. In this apparatus, a plurality of planetary rollers which are arranged to rotate around a sun roller while rotating on their own axes are held by carriers. Filter belts are wound around an outer side of the planetary rollers and are tracted.
In the apparatus of this conventional art, since the direction of movement of the planetary rollers is restricted by the carriers, there are required carriers that securely hold the planetary rollers. In addition, since the filter belts are always in contact with the planetary rollers in the same conditions, a high rate of dewatering cannot be obtained.